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300s School/ME 2150 - High Assurance Cyber-Physical Systems/ME 2150 - High-Assurance Cyber-Physical Systems Homework 1.md

@@ -5,4 +5,8 @@ Alex sought out the position at the Wheelchair and Cushion Standards Group as an
 
 Wheelchair cushions are a surprisingly sophisticated device, and far from only a piece of foam. Wheelchair cushions are critical for users who spend a large amount of time in their wheelchair, and an effective cushion can play a significant role in the overall health of the user. Cushions redistribute the weight of a wheelchair user evenly across their buttocks, while an insufficient cushion can create problems for wheelchair-bound individuals including ulcers, posture issues, and blood flow restrictions. These problems are even further magnified for individuals who have loss of feeling in their legs, as they can not detect the development of injuries until they are visibly apparent or manifest in greater health issues. For these reasons, regulatory standards exist for wheelchair cushions. Standards such as [ISO 16840-2](https://www.iso.org/standard/84862.html) exist to protect wheelchair users by providing a standard to which cushions can be tested. By using wheelchair cushions that meet these standards, users can have a degree of assurance that the product they're using will minimize risks associated with prolonged wheelchair use.
 
-For a wheelchair cushion to pass this standard, it must be experimentally tested. 
+For a wheelchair cushion to pass this standard, it must be experimentally tested. This testing is commonly done by companies that specialize in standards testing. The sensors and equipment required to do ISO testing can be very expensive, and prohibitive for individual manufacturers of items like wheelchair cushions to create test fixtures of their own. Pitt's Wheelchair and Cushion Standards group does such testing for this particular wheelchair cushion standard using a testing rig that is described in the following image.
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+![[press.png]]
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+This testing fixture consists of a hydraulic press with a specific CNC-machined wooden buttocks model attached. These buttocks integrate an array of pressure sensors at a speckling of locations in order to gather a holistic understanding of the distribution of pressure on the buttocks surface. A cushion is fixed to the lower part of the hydraulic press frame